i know
Code: (condition) ? true-clause : false-clause
but how do you use an array as the condition, how will the code look?For example i want to write
Code:
string numbers[5] = {"one","two","three","four","five"};
numbers == "one" ? thumb : again; thumb and again will replace something else. Don't worry about them.
how do i say that if the numbers array is representing "one" then it replaces as "thumb", otherwise "again".
I want to know if it's valid to use and/or when using the conditional operator.
Example:
value = textBox1.Text;
decimal? qty = (value.Equals("0") || value.Equals("0.0")) ? null : (decimal?)decimal.Parse(value);
So I think I am having syntactical problem with my code.
Code:
int main() {
vector<int> ivec;
int score;
[Code] ....
I get an error from my compiler on the ?10th? line (Nested condition line) that says |19|error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<<'|
The purpose of the program is to take input and store it in a vector and then change the value to be between 1-6. I made this for the purpose of learning about nested conditional operations.
I am trying to use getline as the conditional for a while loop as seen below.
string filename, guard_name;
int call_number;
vector <Seniority> SeniorityList;
ifstream SeniorityFile;
[Code] ....
However, when I compile the code, I get the following error message on the line with the while loop.
error C2780: 'std::basic_istream<_Elem,_Traits>
&std::getline(std::basic_istream<_Elem,_Traits>
&,std::basic_string<_Elem,_Traits,_Alloc>
&)' : expects 2 arguments - 3 provided
The program will be reading in a .csv file, so I need my program to be able to deal with values separated by commas. Is there a reason why it will not accept that conditional statement?
I'm facing a serious problem with udp protocol. I have Master & Slave devices.I did implement the class as the follow pseudo code states
In Master side
while (true)
{
1-send data to slave;
2-get data from slave;
3-apply force;
}
In Slave side
while(true)
{
1-get data from master;
2-if (collision happnes)
send force to the master
}
the problem is in line 2 in Master side. Once I include the line I can't send or receive data. What do you think the problem is?
I'm playing with my final year project, building a game boy emulator in C, and I wanted to try out something to streamline my code base. I'm building against Win32, GNU C and Googles Native Client.There are no platform specific headers or functions in use. What I'm trying to do is have a file that conditionally includes the entry point (so _tmain for Windows etc) based on a preprocessor directive being set/not-set.
[note] I realise I could write both entry point classes in one file and use the preprocessor directive in there, but it's not as neat as a single file calling in one or the other. I figure this should work because I can conditionally include headers for Win/NaCl (providing the signatures match, of course).
I am looking for a way to declare variables at run time which being a static language shouldn't happen. I will explain my situation.
I am upgrading a legacy program that modifies executables (non malicious). I am trying to add 64bit support.
It is a huge project and I understand the majority of it but my issues with how it handles the input data.
It has a struct that certain parameters of the input file is loaded into:
Code:
typedef struct DATA {
DWORD Size;
IMAGE_NT_HEADERS32 Headers;
} _DATA; *PDATA
etc, etc its a huge list.
My problem lies in the fact that I need to change IMAGE_NT_HEADERS_32 to IMAGE_NT_HEADERS64 at runtime.
That DATA struct gets called at least 110 times during runtime.
How I might tackle this? Having a conditional statement repeated that many times seems ridiculous.
I have the following code:
Code:
while (lineread != "
")
{
getline(ifs,lineread);
}
In essence, it reads an input file, line by line until it hits a line only containing a newline character. So if the input text file is:
27
GC0123456
102905908801170--
2034068010201360
3039077011601400
4043086012901400
504709401400
6051010101400
[code]....
It should exit the while loop after hitting line 6. What happens however is that it goes into a perpetual loop and doesnt exit the while loop upon reading line 6.
What I did was changed the code to:
Code: while (lineread != "*")
{
getline(ifs,lineread);
} and the input file to:
27
GC0123456
102905908801170--
2034068010201360
3039077011601400
4043086012901400
[code]....
and finally it stops after line 6. In this case, merely changing the " " conditional character to a simple asterisk character "*" fixes the problem.
However I wish to keep the input text file as is with the newlines, so how do I make it exit the while loop when detecting a as a line?
I'm making a program to draw a trajectory, was using as a basis the tangent, but when I put 90 degrees, the tangent is very large, so I thought of putting an if (angle == 90) did not use the tangent.
the design is right, but after choosing it 90 degrees it stops to draw.
for example
1-30 degrees - draws
2-45 degrees ---- draws
3 draws -90 degrees ---
4-60 degrees --- not drawing
5 --- 80 degrees --- not drawing
*
*
making routine design is presented below:
void Draw() {
glColor3f(1.0, 1.0, 1.0);
glBegin(GL_LINES);
convert(graus);
if (ant){
x=xx;
y=yy;
[code]....
I am getting this message from Valgrind, As far as I can see what it points to is initialized. The memory it is referring to is freed in unload and I was not getting this error until after I added the check function. Valgrind was happy. Here is the code and the error message from Valgrind. I am trying to create a spell checker for an assignment for a online class I am taking. I just want to get this table working correctly before I add it to the rest of the program. The code seems to run fine but I have come to see that dos not mean much in C.
#include "hashTable.h"
#include <stdbool.h>
table_node hash_table[TABLE_LENGTH];
bool loaded = true;
//assigning letters a-z to table nodes for buckets
void key_hash_t( )
[Code] ....
Valgrind error:
arortell@gentoo ~/Development/Projects/C_Projects/Data_Structures/HashTable $ valgrind --leak-check=full --track-origins=yes ./hashTable
==11360== Memcheck, a memory error detector
==11360== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==11360== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==11360== Command: ./hashTable
[Code] ....
I want to do conditional compilation based on whether it is windows 7 or windows 8. Here is the code below.
#if (_WIN32_WINNT >= 0x0602) //Condition to check whether it windows 7 or 8 .Based on this we can load msxml 3 or 6.
#import <msxml6.dll>
#else
#import <msxml3.dll>
#endif
Im building the above code in windows 8 machine.
Issue here is _WIN32_WINNT should have a value 0x0602, it means it is running in windows 8 machine.Instead it has a value 0x0601 (Means it is taking windows version as windows 7 defined in sdkddkver.h).Im not sure after installing windows 8 sdk im not able to see any include or lib files in the path below C:Program Files (x86)Microsoft SDKsWindowsv8.0A . but i can see all include and lib files of sdk version v7.0A available although i did not installed it.
I have airport class which should navigate planes, in its list to runways, with method move, theres a method prepare which changes the direction of flight to all planes, always before move is called, move just increments decrement x and y of plane in its list. But after calling two times in row airport->move(), I get screwed and I really dont know wheres the problem. Have I badly initiazed something? Iterator gets invalidated.
Valgrind Stacktrace
Conditional jump or move depends on uninitialised value(s)
==26207== at 0x409601: plane::move() (in /home/xnovak11/Downloads/airport/main)
==26207== by 0x401FBD: airport::move() (in /home/xnovak11/Downloads/airport/main)
==26207== by 0x405FE1: io::start(std::istream&, std:stream&, std:stream&) (in /home/xnovak11/Downloads/airport/main)
This is how I add planes into list in airport
Code:
list<plane*> planes;
list<plane*>::const_iterator planeIterator;
list<plane*>::iterator planeIteratorMoj;
bool airport::addPlane(const plane& p) {
[Code] .....
This is the method where it fails. When I call it once, no problem, after second call I get instead of normal number in cout<<after move<< s1 i get like 8795456 ....
Code:
void airport::move() {
for(planeIteratorMoj = planes.begin(); planeIteratorMoj!= planes.end(); planeIteratorMoj++) {
plane * p1 = (*planeIteratorMoj);
int s,w;
p1->getPosition(s,w);
[Code] .....
I'm doing a refresher for C++ and have gotten to operator overloading. I'm trying to perform an operator overload with the insertion (<<) operator, but I have encountered a problem.
Here's my class [In a header file "Shinigami.h"]
#include<string>
namespace K{
class Quincy;
class Shinigami{
friend std::ostream& operator<<(std::ostream&, const Shinigami&);
[Code] .....
If the operator function is a friend of the 'Shinigami' class, why doesn't it recognize any of it's private members? I need it to be in this file because I'm doing a bit of association with the 'Quincy' class.
I thought it was the namespace, but I included that.
Is it usual to rely completly on the new operator in constructors/copy constructors. What if new trows an exception? The application ends and that's it? The new operator can be placed where it can't be catch like in constructor initialization list. What kind of practice I should adopt when using "new" in those cases?
The sample code below is taken from here... [URL] ....
class MemoryBlock {
public:
// Simple constructor that initializes the resource.
explicit MemoryBlock(size_t length)
: _length(length)
, _data(new int[length])
[Code] .....
In this below example:
class Point {
private:
double m_dX, m_dY, m_dZ;
[code].....
In that situation, << does not call the overloaded function, but rather calls the << method defined in the i/o library, which prints a message to the controlling terminal. So once it prints the message to the terminal, it then returns the out instance. Why return the out instance rather than a boolean like true? As you can see from the example, once the message is printed to terminal, out is not used anymore.
Here's my question. I'm coding a basic Linked List class (for the purpose of understanding and having fun, I know about STL), LList.
I have overloaded the [] operator so it returns the data of the index-th node in the list, for example, if I code
LList x;
....
cout<<x[5];
it prints the data of the 5th node in the list (for fun I decided to index from 1 to infinity).
My question: Now I want to be able to assign the value to the index-th node data, using [] and =, for example, I want to be able to write:
LList x;
.....
x[5] = 121;
How can I do that?
1.WAP in C++ to enter marks in 3 subject and calculate percentage and grade.cond given below (Using Ternary operator)
Per Grade
90-100 A
80-90 B
70-80 C
0-70 D
2. WAP to enter 3 no.s in and print them in ascending and descending order .(Using Ternary operator)
In stl map, if I insert two keys, say a and b. It looks like compare operator is called twice. First time a<b is called and second time b<a is called. Why are both a<b and b<a called?
View 6 Replies View RelatedHere is the code,
Code:
class A {
private:
void* operator new(size_t size);
};
int main() {
return 0;
}
The code above compiles fine without errors. But operator new might not have implementation body?
I am working on this assignment...
Code:
#include <iostream>#include <iomanip>
using namespace std;
class Score
{
private:
// Value at which we'll shift digits from million_counter to billion_counter
static const int THRESHOLD = 1000000000;
[Code] ....
It gives the errors:
line 105 error: million_counter was not declared in this scope
line 106 error: normalizeScore was not declared in this scope
line 110 error: million_counter was not declared in this scope
and more of that until
line 170 error: no match for 'operator<<' in 'std:perator<< <std::char_traits<char> >((* & std::cout), ((const char*)"a+b is ")) <<operator+((*c(const Score*) (& a)), (*(const Score*)(& b)))'
I thought that because i declared friend functions, they would be able to access the private variables of the class.
I understand that the dot operator is:
Code: a.b "a"
is the actual object (not a memory location) and "b" is the member. I also understand the arrow to mean:
Code: a->b "a"
is a pointer to a struct and "b" is it's member so "a" is dereferenced then "b" is given.
Here is where I get a little confused. I have a class:
exampleclass.h
Code:
#ifndef EXAMPLECLASS_H_INCLUDED
#define EXAMPLECLASS_H_INCLUDED
class exampleclass{
[Code].....
Also if ec1 had a public variable and I wanted to access it would it be referenced the same way as the method I call in ec1?
I have done alot of googling for the scope resolution operator and Ive gained a bit of an understanding as to what it does i know it can distinguish between global and local variables, but I see it used to access methods/members of classes such as this example, why not just use a dot instead to access it?:
sql:: Driver *driver;
Why is the scope resolution operator being used here?
Code:
while ((y % 12) != 0) {
y++;
}
I liked that the above code does not put the result into a variable and then test the variable which would use more memory, and more lines of code. Is this thinking bad?
Well... I observed, as a non-professional programmer that "overloading operators" has some strict rules and some conventions... so any operator can differ from another. In order to have a clearest idea, I'd like to ask you to specify, for every operator, the correct (or best) way to overload it.
There are cases where you define &operator and cases where you define operator (without "&"). There are cases where operator are defined as "friend" inside class, and other cases where operator is declared externally.
example: ostream &operator<<
(why it uses & ??)
So can we have a summary for all kind of operators?
How would i be able to overload a multiplication operator that if, in the main example(0, 5, 0) * example (0, 5, 0) is given, it gives me 25?
View 1 Replies View RelatedI keep getting an undesired value in this code. I've tried several methods, but none are giving me the correct answer. The out put is always zero, when in this case it should be 10!!
Here's the object structure:
template<class T, class _b>
struct quantity {
private: T value;
public:
explicit quantity(T val): value(val) {};
T getValue() { return value; };
[Code] .....
Here's the operation:
int main() {
quantity<int, bool> m(20);
quantity<float, bool> m_f(10);
quantity<double, bool> m_d(NULL);
m_d = m_f;
[Code] .....
Why does it seem that the assignment operator is the harder operator to overload? Maybe it's just my luck, but I seem to always run into issues whenever I work with it. I hardly ever experience errors when overloading any of the other operators.